The scans that that companies like 23andme complete are for common SNPs (single nucleotide polymorphisms), not full DNA sequencing, which is much cheaper but provides only a sample of your genotype.
Research scientists use the same technology to conduct GWA studies (Genome Wide Association), which seek to determine if these SNP's are associated with a disease phenotype across a population. These studies typically find one or two SNP's that are associated with a disease (e.g. Breast Cancer, Diabetes, Macular degeneration, etc), but with extremely small odds ratios. These studies help narrow down possible genetic areas of interest for other researchers.
As they are population based studies, they are of no use clinically at all. As one of the first people to document the GWA study methodology put it:
"Patients inquiring about genomewide association testing should be advised that at present the results of such testing have no value in predicting risk and are not clinically directive." ~ Teri A. Manolio. Genomewide association studies and assessment of the risk of disease. The New England Journal of Medicine, 363(2):166–176, July 2010
The trouble is that companies like 23andme tell their clients that because they have a particular SNP, they are likely to get a disease which is extremely disingenuous. They do this by reporting the odds ratio found by a GWA study as their personal odds ratio of getting a disease. The research they use to make their findings is not applicable to single cases yet they claim it is. This leads to stress in clients and then ties up medical resources better spent chasing actual disease, rather than phantoms.
I'm all for open access to genetic data, but the current crop of consumer genetic companies are pedalling fear rather than open information, and probably deserve to be regulated.
Research scientists use the same technology to conduct GWA studies (Genome Wide Association), which seek to determine if these SNP's are associated with a disease phenotype across a population. These studies typically find one or two SNP's that are associated with a disease (e.g. Breast Cancer, Diabetes, Macular degeneration, etc), but with extremely small odds ratios. These studies help narrow down possible genetic areas of interest for other researchers.
As they are population based studies, they are of no use clinically at all. As one of the first people to document the GWA study methodology put it:
"Patients inquiring about genomewide association testing should be advised that at present the results of such testing have no value in predicting risk and are not clinically directive." ~ Teri A. Manolio. Genomewide association studies and assessment of the risk of disease. The New England Journal of Medicine, 363(2):166–176, July 2010
The trouble is that companies like 23andme tell their clients that because they have a particular SNP, they are likely to get a disease which is extremely disingenuous. They do this by reporting the odds ratio found by a GWA study as their personal odds ratio of getting a disease. The research they use to make their findings is not applicable to single cases yet they claim it is. This leads to stress in clients and then ties up medical resources better spent chasing actual disease, rather than phantoms.
I'm all for open access to genetic data, but the current crop of consumer genetic companies are pedalling fear rather than open information, and probably deserve to be regulated.